183rd (Mixed) Heavy Anti-Aircraft Regiment was an air defence unit of Britain's Royal Artillery formed during World War II.

The regiment was heavily engaged in Operation Diver, defending England against V-1 flying bombs, and later was deployed to Antwerp to carry out anti-Diver duties there in the closing stages of the war.

In April its commander-in-chief, Lieutenant-General Sir Frederick 'Tim' Pile, proposed to overcome this by utilising the women of the Auxiliary Territorial Service (ATS).

The ATS was by law a non-combatant service, but it was decided that Defence Regulations permitted the employment of women in anti-aircraft (AA) roles other than actually firing the guns.

[11][12][13] As preparations for the Allied invasion of Normandy (Operation Overlord) gathered momentum, AA Command redeployed its resources in Southern England to cover the assembly areas and embarkation ports.

Defences had been planned against this new form of attack (Operation Diver), but the missiles' small size, high speed and awkward height presented a severe problem for AA guns.

The whole process involved the movement of hundreds of guns and vehicles and thousands of servicemen and women, but a new 8-gun site could be established in 48 hours.

The guns were constantly in action, but success rates against the 'Divers' steadily improved, until over 50 per cent of incoming missiles were destroyed by gunfire or fighter aircraft.

[5][17] The regiment arrived at Antwerp in January 1945, taking over Mk IIC 3.7-inch guns on Pile platforms in bitter weather with inadequate hutting, and were immediately in action against the onslaught of V-1s.

The Antwerp 'X' defences under 80 AA Bde involved an outer line of Wireless Observer Units sited 40 miles (64 km) to 50 miles (80 km) in front of the guns to give 8 minutes' warning, then Local Warning (LW) stations positioned halfway, equipped with radar to begin plotting individual missiles.

Finally, there was an inner belt of Observation Posts (OPs), about 20,000 yards (18,000 m) in front of the guns to give visual confirmation that the tracked target was a missile.